1. Field of the Invention
This invention relates to an optical actuator that uses the voltage generated by the photovoltaic effect of a lead zirconate titanate device (PZT system device) to generate electrostatic force and extract power as rotary motion or linear motion.
2. Description of the Prior Art
Conventional optical actuators that use PZT system devices generate displacement using the photostrictive effect, which is the cumulative effect of the photovoltaic effect and piezoelectric effect of PZT system devices.
Conventional optical actuators that use PZT system devices have problems in that the amount of their displacement is limited because they utilize the strain of the material itself, and their displacement is small even when using a bimorph structure or other magnifying mechanism. In addition, the extraction of rotary motion is also difficult.
The present invention is proposed in order to solve the problems with the aforementioned prior art, and its object is to provide an optical actuator that is able to use light as its input and extract a large amount of displacement as output in the form of rotary motion or linear motion.
In order to achieve the object, the optical actuator according to this invention comprises a pair of stators disposed parallel to each other with a stipulated gap between them, a mover disposed moveably within the gap, and a device having a photovoltaic effect; wherein the device having a photovoltaic effect has a device electrode in one direction of polarization connected to one stator of the pair of stators, and a device electrode in the other direction of polarization connected to the other stator of the pair of stators, and a voltage generated by the photovoltaic effect of the device is utilized to generate force that displaces the mover with respect to the pair of stators by means of electrostatic force arising from the voltage.
The stator may consist of a plurality of stators disposed upon a stator disk at equal intervals in the peripheral direction, the mover consists of a plurality of rotors disposed upon a rotor disk at equal intervals in the peripheral direction, the intervals between the stators and the intervals between the rotors are varied in disposition, and the rotor disk is able to rotate coaxially with respect to the stator disk.
In addition, the stator may also consist of a plurality of stators disposed upon a stator plate at equal intervals, the mover consists of a plurality of movers disposed upon a mover plate at equal intervals, the intervals between the stators and the intervals between the movers are varied in disposition, and the mover plate is able to move linearly with respect to the stator plate.
The device having a photovoltaic effect may be a PZT system device, a lithium niobate device or a polyvinylidene fluoride copolymer device.
With the optical actuator according to the present invention, it is possible to increase the amount of force generated and the displacement rate by increasing the numbers of stators and movers or providing a structure with multiple elements.
The optical actuator according to the present invention utilizes not only the photoelectric effect of a device having a photoelectric effect but also electrostatic force, so a large displacement can be extracted in rotary motion or linear motion.
The above and other objects and features of the invention will become apparent from the following description made with reference to the accompanying drawings.